Fire extinguisher



y 7, 1934. H. w. DOUGHTY FIRE EXTINGUISHER Filed Nov. 2, 1932 2 Sheets-Sheet 1 Patented July 17, 1934 UNITED STATES PATENT ()FFICE FIRE EXTINGUISHER Application November 2, 1932, Serial No. 640,786

5 Claims.

This invention relates to fire extinguishers and particularly to a self-contained fire-extinguishing unit which is adapted to deliver automatically a liquid fire-extinguishing agent when the temperature in the vicinity of the extinguisher rises to a predetermined point.

Extinguishers containing fire-extinguishing and pressure-generating agents are known and are in commercial use, notably apparatus described in Patent No. 1,698,840 issued to me. In that patent, it is pointed out that carbon tetrachloride and concentrated solutions of ammonia in water are among the most effective agents for use in fire extinguishers of the type described. It is also shown that these liquids, in conjunction, exercise an extremely corrosive effect upon most ordinary metals, but that aluminum is not subject to such corrosion.

It is the object of the present invention to provide further improvements in fire extinguishers wherein fire-extinguishing and pressure-generating agents are stored, and particularly to maintain such agents in separate compartments communicating with each other but normally sealed so that communication is established only in the event that the fire-extinguishing liquid is to be released and ejected.

The separation of the fire-extinguishing and pressure-generating agents avoids any possibility of corrosion, even though the receptacles for these agents are not resistant to the combined action thereof. The extinguisher is thus adapted particularly for use with carbon tetrachloride and aqueous ammonia solutions which jointly corrode most metals other than aluminum. Other fire-extinguishing and pressure-generating agents may be used, however, in the extinguisher as hereinafter described.

In carrying out the invention, I provide a receptacle for the fire extinguishing agent with an outlet having preferably a sprinkler head to distribute such agent over the area surrounding the extinguisher. The outlet may be controlled as shown in Patent No. 1,698,840. The details of the outlet and distributor may, however, be varied and may include the dual control features of Patents No. 1,736,255 and No. 1,736,256 issued to me. These features may be omitted if the particular advantages thereof are not desired.

I provide a separate receptacle for the pressure-generating agent outside the principal receptacle for the fire-extinguishing liquid. This separate receptacle for the pressure-generating agent may be variously disposed at the bottom,

top or side of the principal receptacle, or it may wholly or partially surround that receptacle. A convenient arrangement is to place the receptacle for the pressure-generating agent at the bottom of the principal receptacle. It may, however, be arranged in the form of a coil surrounding the principal receptacle.

In any of these arrangements, I provide a communicating passage between the principal receptacle and the receptacle for the pressure-generating agent. This may be a pipe or merely an rifice or fitting, depending upon the arrangement selected. It should-provide access for gas formed in the pressure-generating receptacle to the space above the liquid in the principal receptacle.

The passage or orifice or other means of communication is normally sealed. This may be accomplished by providing a cap or diaphragm which is held in place by a low melting point solder adapted to be melted and therefore to release the pressure-generating agent when the temperature rises to a predetermined point. The cap or diaphragm also includes a portion which may be made of a frangible material such as metal foil, aluminum, gold or silver foil for example, which is adapted to be ruptured when the pressure in the pressure-generating chamber rises to a predetermined point. The complete sealing is effected by a combination of these devices so as to provide dual control, the gas being released only when both the temperature and pressure are above predetermined points to avoid possibility of premature entrance of gas under pressure into the receptacle for the fireextinguishing liquid.

In the apparatus as described, the fire-extinguishing and pressure-generating agents cannot mingle until the predetermined conditions requiring discharge of the fire-extinguishing liquid prevail. Consequently there is no danger of corrosion due to the joint efiect of these agents. Thus, carbon tetrachloride and aqueous ammonia solutions can be employed, even though the apparatus is constructed of metals other than those which resist the joint action of these agents. Common metals such as iron, copper and brass may be used in constructing the apparatus, although it may also be made of aluminum, which has advantages owing to its high heat conductivity.

When the predetermined conditions arise, the pressure-generating agent releases gas and builds up the pressure. The gas under pressure is permitted to enter the space above the fire-extinguishing liquid when the seal between the two receptacles is broken through melting of the solder and rupture of the diapln'agm. The fireextinguishing liquid is ejected and sprayed over the surrounding surface if and when the seal in the sprinkler head is likewise released as the result of the increase in temperature. The fireextinguishing liquid is thus sprayed over the surrounding surface and extinguishes the fire which caused the increasing temperature and'the'release of the liquid.

In the accompanying drawings, I have illustrated a typical example of an extinguisher embodying the invention. As hereinbefore noted, the particular arrangement of the parts is subject to numerous modifications, and the drawing is, therefore, not intended tolirnit the invention with respect to details. In'the'drawings;

Fig. 1 is a vertical section through the-extinguisher;

Fig. 2 is a section on the line 22 of Fig. 1;

Fig. 3 isa vertical section through a modified form of extinguisher;

Fig. 4 is a section on the line 44 of Figure 3;

Figures 5 and 6 are details of modified forms of means for uniting and closing the passage between the receptacles ior the two different liquids; and

Fig. 7 is a vertical section through the lower portion of an extinguisher having the sprinkler disposed atthe bottom thereof.

Referring to the drawings, 5 indicates the principal receptacle whichds substantially filled with thefire-extinguishing liquid, such, for example, as carbontetrachloride 6. The principal receptacle may be constructed of any suitable metal or other material adapted to serve the purpose. A pipe 7 extends from a point near the bottom of the receptacle 5 through the top'thereof to provide an outlet for the liquid contents. The outlet is normally olosed by a cap which is adapted to be opened under fire temperature. This may comprise a diaphragm of metal foil 8 held in place by two washers mounted in'a support 10 which is threadedly mcuntedon the end of the pipe 7, and the opening may be filled with low melting point solder 9, all as described in detail in my Patent No. 1,736,256. A deflector 11 is mounted on the support 10 to spread the fire-extinguishing liquid when it is ejected. The assembly, including the cap, fusible link and the support,-constitute the usualtype of sprinkler head and may be modified as desired, for example to include the control features OtPatents No, 1,698,840 and No. 1,736,- 255.

At the bottom of the 1'eceptac'le5 I provide a second receptacle 12'which may be of smaller dimensionsand alsomade of any suitable metal to hold the pressure-generating agent, such, for example, as an. aqueous solution of ammonia. The receptacle 12 communicates'with the interior of the receptacle 5 through aipipe 13, the upper end of which extends above the liquid level in thereceptacle 5. Theupper end of thepipe 13 is closed by a capwhich includes amember 14 secured by easily fusible solder 15. The melting point of the solder should be such as to release the portion 15 of thecap when thetemperature rises to the point at'whichdischarge .of the fire-extinguishing-liquid-isdesired. Thusgin the'eventof: a' fire, the cap will be released and the gases generated by the rising temperature in'the receptacle 12 will-enter the receptacle '5, and upon release-of the sprinkler head the -fire-extinguishing liquid will-be ejected. 7

The portion 14 of the cap may be of relatively thick metal or, if desired, it may be made of a comparatively thin metal foil, for example, aluminum, gold or silver foil of a thickness such that it will be ruptured when the pressure in the receptacle 12 and pipe 13 reaches a certain predetermined point. When the portion 14 of the cap is made of comparatively thin metal foil,.it may be secured in place by extending it over the edges of the pipe 13 and pressing it into the threads on the upper end thereof as shown at 14'. The solder 15 may thereafter be threaded onto the threads over the metal foil which is pressed thereinto. In that case, when the temperature has increased sufiiciently to melt the solder 15 and the pressure in the receptacle 12 and tube 13 increases suiliciently to rupture the portion 14 of the cap, the pressure-generating agent will be discharged intothe upper portion of the receptacle 5 and may cause a discharge of the fire extinguishing fluid'therefron'i when a similar release occurs at the'spi'inkler head.

A removable plug 16 may be provided in the top of the receptacle 5 to-permit refilling of the separate receptacles, and the replacement of the cap when it has been-removed or rupturedin the operation of the apparatus. A suitable bail 1-7 or other support may beprovided to facilitate placing the extinguisher inproper position for protection of surrounding surfaces. Obviously, the sprinkler head may be disposed at the bottom rather'than at the topof the-apparatus in which case the pipe 7a extends from the interior of the receptacle 5 through the receptaclelZ at the-bottom, but the pipe 7a does not, in thiscase, extend beyond the bottom of the receptacle '5, so that the liquid contents will be forced from the receptacle by the gas released from the receptacle l2.

In'the extinguisher shown in Figure 3, the receptacle 20 for holding the solution of ammonia or other pressure-generating agent encircles the receptacle 21 for the carbon tetrachloride -or other extinguishing liquid, and the two receptacles are connected by an external passage 22,23. The two passages are connected by a union 24, 25. The threads 26 areleft-hand threads and the threadsZ? a-reright-hand threads,"so that on turning the part 250i the union (which may have an outer hexagonal cross-section to facilitate turning), the two passages are drawn'together and a tight-joint is formed. The two passages are separated'by the diaphragm 28 which is of'metalfoil of such strength that it will be ruptured 'by the pressure produced in the outer receptacle 26-at fire temperature. The diaphragmis held in place by washers 29. The diaphragm keeps the two liquids from mixing. When the extinguisher is subjected to fire temperature, the pressure-generated 'in the outer receptacle ruptures the diaphragm iand the gas thus released'f'orces the fire extinguishing liquidt-hrough the outlet 'tube 7. It is ejected against the-spray head :11 with sumoientforce to sprayit over the surroundings.

Modified and preferred means for uniting and closing the passage between the receptacles 20 'an'dl21 are shown in Figures5 andfi. Figure5rineludes a fusibleplug :30'-which.may:be formed by inserting a wooden plug'in the opening 31 and pouring in solder which will be supported bythe shoulders 32. .After the solder has set, the wooden plug will beremoved. The washer '33Wi11 then be putinto positionaand'vaseline-34,:or:other suitable low :melting material will be introduced ln'to'the cavity thus formed in suflicientamountto just fill the space to the level of the washer 33. This serves as a support for the diaphragm 35 which is foil of any suitable metal. After placing the diaphragm in position the washer 36 is introduced and the union completed.

Figure 6 shows another form or fusible link in which a cap of solder 40 is soldered to the threaded metal tube 41. In other respects the coupling shown in Figure 6 is similar to that shown in Figure 5. When the coupling is subjected to fire temperature the solder melts and the diaphragm is ruptured by pressure of the gas generated in the receptacle 20. The gas then escapes to the receptacle 21 and the carbon tetrachloride or other extinguishing liquid is forced against the spray head 11', the diaphragm 8 and seal 9 being broken by the heat and pressure.

The various illustrations shown in the drawings suggest various modifications of structures which may be utilized in keeping the liquids separate in extinguishers of the types shown in Figures 1 and 3.

As will be readily understood, the fire-extinguishing and pressure-generating agents are maintained separately in the apparatus and cannot come together or mingle until conditions arise which require delivery of the fire-extinguishing liquid from the apparatus. No corrosion can occur, therefore, in the apparatus, even though it is maintained without operation for long periods of time. Whenever the temperature rises suificiently, as for example when a fire occurs, the gas generated in the pressure-generating chamber is promptly released and becomes available to force the fire-extinguishing liquid from the apparatus.

Various changes may be made in the details of the construction and arrangement of the parts as hereinbefore indicated, without departing from the invention or sacrificing any of the advantages thereof.

I claim:

1. A fire extinguisher comprising a closed principal receptacle for fire-extinguishing liquid, outlet means constructed and positioned to normally prevent discharge of the liquid therethrough and adapted to be open at predetermined fire temperature, an independent receptacle outside the principal receptacle adapted to hold a fluid capable of generating a gas under pressure when the temperature rises, a passage between the two receptacles, heat sensitive means, and additional means sensitive to pressure normally closing the passage and adapted to be opened when both said heat and pressure sensitive means have operated.

2. A fire extinguisher comprising a closed principal receptacle for fire-extinguishing liquid, outlet means constructed and positioned to normally prevent discharge of the liquid therethrough and adapted to be open at predetermined fire temperature, an independent receptacle outside the principal receptacle adapted to hold a fluid capable of generating a gas under pressure when the temperature rises, a passage between the two receptacles, and means normally closing the passage and adapted to be opened under the combined action of predetermined fire temperature and predetermined generated pressure including a diaphragm secured in place across said passage and a mass of low melting material which is solid at normal temperatures.

3. A fire extinguisher comprising a closed prin cipal receptacle for fire-extinguishing liquid, outlet means constructed and positioned to normally prevent discharge of the liquid therethrough and adapted to be open at predetermined fire temperature, an independent receptacle outside the principal receptacle adapted to hold a fluid capable of generating a gas under pressure when the temperature rises, a passage between the two receptacles, and means normally closing the passage and adapted to be opened under the combined action of predetermined fire temperature and predetermined generated pressure including a frangible diaphragm secured in place across said passage and a mass of low melting material which is solid at normal temperatures.

4. A fire extinguisher comprising a closed principal receptacle for fire-extinguishing liquid, outlet means constructed and positioned to normally prevent discharge of the liquid therethrough and adapted to be open at predetermined fire temperature, an independent receptacle outside the principal receptacle adapted to hold a fluid capable of generating a gas under pressure when the temperature rises, a passage between the two receptacles, and means normally closing the passage and adapted to be opened under the combined action of predetermined fire temperature and predetermined generated pressure including a metal foil diaphragm secured in place across said passage and a mass of low melting material which is solid at normal temperatures.

5. A fire extinguisher comprising a closed principal receptacle for fire-extinguishing liquid, outlet means constructed and positioned to normally prevent discharge of the liquid therethrough and adapted to be open at predetermined fire temperature, an independent receptacle adapted to hold a fluid capable of generating a gas under pressure when the temperature rises, an external passage connecting the two receptacles and means normally closing the passage and adapted to be opened under the combined action of predetermined fire temperature and predetermined generated pressure including a diaphragm secured in place across said passage and a mass of low melting material which is solid at normal temperatures.

HOWARD WATERS DOUGHTY. 

